Drilling device



Oct. 24, 1961 H. w. MAYHEW, JR 3,005,504

DRILLING DEVICE Filed May 11, 1959 3 Sheets-Sheet 1 63 INVENTOR HermanW. Mayhew,Jr.

ATTORNEY Oct. 24, 1961 H. w. MAY-HEW, JR

DRILLING DEVICE 5 Sheets-Sheet 2 Filed May 11, 1959 Q A KS, 4 ///flflfl/m m INVENTOR Hermon W.Muyhew, Jr.

Oct. 24, 1961 H. w. MAYHEW, JR

DRILLING DEVICE 3 Sheets-Sheet 3 Filed May 11, 1959 INVENTOR Hermon W.M0yhew,Jr.

BY ME ATTORNEY United States Patent 6 3,005,504 DRILLING DEVICE HermanW. Mayhew, Jr., Dallas, Tex., assignor to Gardnet-Denver Company, acorporation of Delaware Filed May 11, 1959, Ser. No. 812,330 16 Claims.(Cl. 175-200) This invention is concerned with a drilling device fordrilling holes into the earths strata and is particularly concerned witha drilling device having a drill stem made up of concentrically arrangedand slidably related tubular members which may be disengagably keyedtogether for rotation wherein the inner tubular member may be withdrawnfrom the outer tubular member to permit the outer tubular member toremain in the hole to serve as a casing for the hole while explosives orother instruments are lowered into the hole.

This application is a continuation-in-part of patent application SerialNo. 652,989 (series of 1948), now abandoned, filed April 15, 1957, byHerman W. Mayhew, Jr., Drilling Device.

In quarrying operations and geophysical exploration it is the practiceto drill a hole into the surface of the earth and lower into such holean explosive charge which is detonated to break up the substance to bequarried, or to supply a detonating impulse for recordation ofgeophysical information.

It has been the practice in the past to withdraw the entire drill stemfrom the hole prior to lowering the explosive charge therein, and theexplosive charge was usually lowered into the open hole on wires orcables extending from the surface.

In many areas where such operations are carried-onthe formations of theearth through which the hole is drilled are of loose, crumbly nature sothat when the drill stem is withdrawn from the hole the walls of thehole often crumble and slough off, thereby partially filling the holeand making it ditficult, if not impossible, to lower the explosivecharge into the hole, thereby resulting in added expense and time to theoperator in carrying out such operations.

The present invention comprehends a drilling device which permits theoperator to lower the explosive charge through a casing or liner, whichis a part of the drill stem, so that the walls of the hole cannot cavein to prevent the lowering of the explosive charge therein.

The invention includes concentrically arranged and separately raisabledrill pipes, each having a drill bit thereon, so that the outer drillpipe may be left in the hole when the inner drill pipe is withdrawn toprovide a cased hole through which explosives and other devices may belowered into the hole.

The separately withdrawable drill pipes. are keyed or splined togetherfor rotation in unison so that the two drill pipes, when so keyedtogether, perform the function of a single drill stem.

Thus this device assures a free passage to the bottom of the hole forlowering explosives and other objects therein.

It is therefore a primary object of this invention to provide a drillingdevice which permits the operator to lower explosive charges into thehole through a tubular casing forming a part of the drill stem.

Another object of this invention is to provide a drilling device forquarrying and geophysical exploration which results in a great saving intime and expense to. the operator.

A still further object of the invention is to provide a drill stemhaving concentrically arranged and slidably related tubular parts whichmay be keyed together for unitary rotation but which are separatelywithdrawable from the hole.

' a bore hole 15 therein.

An additional object of the invention is to provide a drill stem made upof concentrically arranged tubular.

members wherein the inner member may be withdrawn FIGURE I is a sideelevational view showing one emr bodiment of the drilling device mountedon the frame of a truck, with the drill stem extending-into a hole whichhas been drilled in the earths surface;

FIGURES II, III andIV show a fragmentary, partially sectionalized,elevational view of a drilling device incorporating the inventiondisclosed herein, said view illustrating the concentrically arranged andseparately raisable drill pipes, keyed together to rotate as a singledrill.

stem;

FIGURE V is a cross-sectional view taken on the line VV of FIGURE III;

FIGURE VI is a cross-sectional view taken on VI--VI of FIGURE II;

FIGURE VII is a bottom plan view of the drill bit-attached to the lowerend of the inner drill pipe;

FIGURE VIII is a bottom plan view ofthe drill bit attached to the lowerend of the outer drill pipe;

FIGURE IX is a cross-sectional, elevational view of a modified. form of.spindle and adapter head showing a. bayonet joint type of connectionbetween such members;

FIGURE. X is a transverse sectional view taken on the line X-X of FIGUREIX;

FIGURE XI is a side elevational view, showing the bayonet jointconnection between the spindle and the adapter head.

In the drawings numeral references are employed to indicate the variousparts shown, and like numerals indicate like parts throughout thevarious figures of the drawings.

vIn FIGURE I is shown a suitable form of mast 10 to support the drillstem as it is rotated to penetrate the earth to form a hole therein, andto provide a supporting frame for raising and lowering the drill pipes,as will be hereinafter described.

The mast 10 may take dilferent forms, but it is preferably mounted on atruck 24 or trailer for the purpose of vide such feature the oppositelegs of the mast 10 may be pivotally mounted to the truck frame 13 bymeans of pivot bolts 11 and when in upright position, as shown in thedrawing, it may be detachably secured to the truck frame by means of abolt and nut 12, or by other suitable detachable securing means.

The drill stem, indicated generally by the numeral 14;

is made up of concentrically arranged and slidably re,

lated tubular members which are keyed together for rota f tion inunison, as will be hereinafter described. As shown in FIGURE I, thedrill bits 67 and 74, attached to the lower ends of the concentricallyarranged drill pipes, have been rotated to penetrate the earths strata16 to form The drill stem 14 slidably extends through, and is keyed to,a rotary table 18, rotatably attached to the frame 13 of the truck, thedrill stem 14 being keyed to the rotary table 18 for rotation therewithby means of a drive bushing as- I sembly 17, which will be hereinafterdescribed in detail,

the line The rotary table 18 may be rotated in any suitable manner as bya drive chain 1'9, extending thereabout, from power supplied by a powerunit 20, mounted on the truck 24. The drive chain 19 may be rotated todrive the rotary table 18 through a gear train driven from the powertake-01f 25 of the power unit 20, such gearing being illustrated asarticulating bevel gears 21 and 22 which drive a horizontally disposedsprocket 23, about which the drive chain 19 is arranged.

The drill stem 14 may be suspended to the mast it by nieans of a cable29 attached to the bail 26, the ends of said bail being pivotallyattached on opposite sides of the rotary spindle 27.

The cable 29 is wound and stored about a rotatable drum 30 mounted onthe truck frame 13, said drum being rotatable by means of a belt 31which is driven by a suitable power take-off (not shown) of the powerunit 20.

The cable 25 extends about a sheave 32, which is rotatably mounted atthe upperend of the mast it). A hook 33, attached to the end of thecable 29, is engaged with the bail 26 to thereby suspend and support thedrill stem 14, and by which the outer drill pipe 65 may be raised out ofthe hole 15 in the manner hereinafter described.

Another cable 34 is wound and stored about a drum 4d, rotatablymounted'on'the truck frame 13, which drum may be rotated by a drive belt41 from a power take-01f (not shown) of the power unit 20.

The cable 34 extends about a sheave 35, rotatably attached at the upperend of the mast 10.

A hook 36, onrthe end of the cable 34, may be attached tothe eye 37,provided on the rotary swivel 28, for the purpose of withdrawing'theinner drill pipe 64 from the outer drill pipe 65 in the manner whichwill be hereinafter described.

V A fluid circulating hose 38 is attached between the rotary swivel orcirculating head 28 and a pump 39, mounted on the truck frame 13.Suitable circulating fluid, such as liquid or air, may be forced throughthe hose 38, the circulating head 28, and downwardly through the innertubular member 64 of the drill stem 14 to thereby provide fluidcirculation through the drill stem 14 and upwardly through the. annularspace between the wall of the bore hole 15 and the drill stern asdrilling is progressing.

Referring to FIGURES II, III and IV, which show the concentrically andslidably arranged tubular members making up the drill stem 14, theannular spindle body 42 is rotatably mounted on upper and lower rollerbearings 43 and 44. The bearings43 and 44 are maintained in assembledposition about the spindle body 42 by means of a bearing retainer ring45 and a spacer sleeve 45a, arranged about the spindle body 42.

The bearing retainer ring 45 has diametrically opposed ears 46 and 47arranged on the outer side thereof about which ears the free ends of thebail 26 are pivotally attached to thereby provide'means for hingedlysupporting the drill stem. 7

Upper and lower fluid seals 48 and 49 are disposed between the bearingretainer ring 45 and the spindle body 42. to maintain lubricating fluidin the reservoir 54 of the b'earing'assembly. The bearings 43 and 44,and retainer ring 45, are held in assembled position with relation tothe spindle body 42 by means of a retainer nut 54 which is threadedlyengaged about the lower end of the spindle body 42, the retainer nut 50being held in place against rotation by means of a set screw 51 whichpasses through the retainer nut 50 and penetratingly contacts thespindle body 42; g

It will be seen that the spindle body 42 may rotate on thebearings 43and 44 as the drill stern, attached thereto, is rotated.

- A lubrication supply passage 52 extends through the ear 46 and may beclosed at its outer end by a removable plug 53. Suitable lubricationfluid may be supplied to the lubricant reservoir 54, in the bearingassembly, through the passage 52.

An insertable and withdrawable inner adapter head 56 is slidablydisposed in the spindle body 42, the said adapter 56 having an enlargedhead 57 thereon which is arranged to come into mating contact with theupper end of the spindle body 42 to thereby suspend the adapter head 56in the spindle body 42.

An upwardly extending attachment neck 55 is provided on the adapter head56, which neck 58 is threadedly engaged at its upper end to the rotaryswivel 28.

The rotary swivel 25 is detachably secured to the hose 38 by a coupling38a.

The rotary swivel 28 is of conventional construction, having a fluidpassage (not shown) therethrough, and includes a tubular part 55 whichis rotatable, in sealed engagement, with reference to the main body ofthe rotary swivel 28. As the drill stem 14 is rotated the tubular part55 rotates with respect to the main body of the swivel 28. Drillingfluid is circulated through the hose 5% and the rotary swivel 28 intoand through the inner pipe 64 of the drill stem 14 and upwardly throughthe hole 15 to the surface.

A concentric flow passage 59 is provided through the inner adapter 56whereby fluid may be circulated through the rotary swivel 28 anddownwardly through the inner tubular member 64 of the drill stem.

A plurality of longitudinal keys or splines 60 are formed, in spacedrelationship, about the outer side of the inner adapter 56, said keysbeing arranged to be inserted in coinciding key channels 61, formed onthe inner side of the spindle body 42. The keys 66 are slidably insertedin the key channels 61 so that the inner drill pipe 64, attached to theadapter 56-, may be drawn upwardly out of the outer driil pipe, but saidkeys 6% and key channels 61 disengagably key the inner drill pipe withthe outer drill pipe, whereby they may be rotated together, v

After the inner adapter 56 has been inserted in the spindle 42 with thekeys 6%) and key channels 61 in mating relationship, a hammer nut 62 maybe threadedly engaged about the upper end of the spindle body 42, inengagement with a shoulder 57a on the head 57 of the inner adapter 56,in order to disengagably attach the inner adapter 56 in the'spindle body42.

The hammer nut 62 has hammer lugs 63 spaced thereabout which may bestruck by a hammer or-other instrument to rotate the hammer nut tothread 'or unthread it about the spindle body 42. The hammer nut 52 maybe disengaged from the spindle body 42 to allow the inner drill pipe 64to be withdrawn from the outer drill pipe 65 as will be hereinafterdescribed.

The lower end of the spindle body 42 is threadedly connected to theouter drill pipe 65 by means of an adapter coupling 66.

The outer drill pipe' 65, as shown", is'cornprised ofa unitary tubularmember. It will'be understood, however, that it could be made up ofseveral sections of pipe joined by suitable couplings or threads.Ordinarily the bore holes drilled in quarrying or geophysicalexploration are relatively shallow so that the outer drill pipe can bemade in one piece, but in the event holes are to be drilled to suchdepth as to require several joints of pipe, such can be provided.

An annular cutting bit 67" is threadedl engaged to the lower end of theouter drill pipe 65, said bit 6'7 having annularly spaced cutting teeth63 formed on the lower side thereof. The bit'67 has a circular passage69 therethrough of sufficient diameter to permit the passage of theinner bit there'through. The outer bit 67 may be engaged with the lowerend of the outer drill pipe 65, after the drill pipe has been passedthrough the rotary table 18, and of course may be replaced when desired.

The inner drill pipe, indicated generally by the numeral 64, passesthrough the outer driil pipe 65 and as shown is made up of a pluralityof sections of tubular members 70 which are threadedly joined togetherby ineans of subs 71. The upper section of the inner drill pipe 64 isthreadedly connectedto the lower end of the inner adapter 56 and issupported thereby when the adapter 56 is keyed to, and suspended in, thespindle body 42, as shown in FIGURE II.

The inner drill pipe 64 has an inner drill bit 74 threadedly engaged tothe lowermost section 70 by means of an adapter sub 72.

The inner drill pipe 64 is of such length as to permit the lower end ofthe inner bit 74 to slightly extend beyond the lower end of the outerbit 67, when the inner adapter 56 is disposed in, and keyed to, thespindle body 42. The inner bit 74 and outer bit 67, when so disposed, ineffect, form one drill bit for penetrating the earth.

The inner bit 74 has a plurality of cutting teeth 76 spaced about thelower face thereof, and between the cutting teeth 76 are flow orifices75 through which circulating fluid may pass when circulated downwardlythrough the inner drill pipe 64. Such fluid passes downwardly throughthe inner drill pipe 64 and outwardly through the orifices 75 andupwardly through the annular space between the outer drill pipe 65 andthe well bore 15 to the surface, in order to provide circulation forcarrying away the cuttings of the bits, and for the purpose of providingcoolant for the bits.

Suitable mechanism is provided for keying the drill stem 14 to therotary table 18 for rotating the drill stem. Such keying mechanism maytake different forms, but the specific form disclosed herein includes asubstantially square-shaped master bushing 79, having straight inner andouter sides, which may be inserted in a mating receptacle (not shown) inthe rotary table 18, whereby the rotation of the rotary table. willrotate the bushing 79.

The master bushing 79 has an annular flange 80 thereon which comes intosupporting engagement with the top of the rotary table 18 when thebushing 79-is inserted therein,

An inner bushing 81, having fiat outer sides and a circular inner side,is arranged to be inserted in, and gome into mating engagement with, themaster bushing The inner bushing 81 has an annular flange 82 thereonarranged to rest upon the upper end of the master bushing 79 to supportsame with reference thereto.

An annular handle 83, which is secured to flange 82 on the inner bushing81 by means of spaced arms 84, is provided for the purpose of allowinghandling and manipulation of the bushing 31 for removing same from themaster bushing 79 or inserting it therein.

A plurality of spaced longitudinal slots 85 are formed on the inner sideof the inner bushing 81, and a squaresided plate 86 is secured to thelower endof the inner bushing 81 by means of a suitable weld, said plate86 overlapping the lower ends of the slots 85 to form a support for thedrive pins 88.

A plurality of spaced longitudinal channels 87, which are complementaryto the slots 85, are formed on the outer side of the outer drill pipe65. The channel 87 extend substantially the entire length of the outerdrill pipe 65. The drive pins 88 may be inserted in the complementarychannels 87 and slots 85 to thereby key the bushing 81 to the drill pipe65.

In assemblying the drive mechanism with relation to the outer drill pipe65, the inner bushing 81 is inserted in the outer bushing 7? and theinner bushing is placed about the outer drill pipe 65. The slots 85 andchannels 87 are brought into alignment and the drive pins 88 areinserted in the coinciding slots and channels. After the drive pins areso inserted a retaining ring 89 is passed about the drill pipe 65 anddisengagably attached to the upper end of the inner bushing 81 by meansof a cap screw 9%). The drive pins 88 may be quickly changed by-removingthe retaining ring 89, thus permitting the drive pins to be withdrawn.

6 It will thus be seen that the inner bushing 81 is slidably keyed tothe outer drill pipe 65 by means of drive pins 88 which may slidelongitudinally in the channels 87. As described above, the inner drillpipe 64 and outer drill pipe 65 are keyed together for rotation inunison by the keys 6t? and key channels 61, and since the outer drillpipe 65 is keyed to the rotary table 18 by the drive as-.

sembly just described, the rotation of the rotary table will rotate thedrill stem, made up of the inner tubular member 64 and the outer tubularmember 65.

The outer drill pipe 65 is permitted to slide downnumber of sections 70to provide sufficient length to.

extend through the outer drill pipe 65, and the inner adapted 56 andswivel 28 are attached to the upper end' thereof. The inner drill pipe64 is run into the outer drill pipe until the inner adapter 56 issuspended in the spindle body 42, with keys 60 and key channels 61 inmating.

relationship. The outer drill pipe may be suspended to the mast 10 bymeans of the cable 29 attached to the bail 26.

The bearing spindle assembly 27 and the drive mechanism 17 are attachedto the outer drill pipe in themanner" hereinbefore described.

The master drive bushing 79 isinserted in the'rotary table in the mannerdescribed, and the bits 67 and 74 are attached to the lower ends of theconcentric drill pipes.v

After the device is thus assembled, as shown in FIGS.

II, III and IV, the circulating hose 38 is connected and it is suspendedto the mast 10 by the cable 29, as shown, The rotary table may then berotated to there-..

in FIG. I. by rotate the assembled drill stem to cause the drill bits todn'll a hole into the earth. As the hole is drilled the drill stem 14slides downwardly through the rotary table.

After the hole has been drilled to a desired depth, the hammer nut 62may be disengaged from the spindle body 42, the cable 34 may be attachedto the eye 37 on the rotary swivel 28 and the inner drill pipe 64 may bedrawn upwardly out of the outer drill pipe 65, thus leav-' ing the outerdrill pipe 65 in the hole.

Before withdrawing the inner drill pipe from the outer drill pipe thehose 38 should be disconnected from the rotary swivel 28.

An explosive charge may then be lowered to the bottom of the holethrough the outer drill pipe 65 and throughthe opening 69 in the lowerend of the bit 67. Such explosive charge may be lowered into the pipe 65onelectric leads through which the charge may later be detonated fromthe surface.

After so placing the explosive charge in the hole, the

outer pipe 65 may then be withdrawn from the hole on the cable 29.Before withdrawing the outer pipe from the hole the end of the innerpipe 64 is placed in the top of the outer pipe 65 and the two pipes aretelescoped together as the outer pipe is pulled out of the hole.

The explosive charge in the hole may then be deto-- nated. 7

After the inner and outer drill pipes have been thus 'telescoped andagain brought into concentric relationship, the hammer nut 62 is againengaged with the spindle body 42 to thereby join the pipe stringstogether.

The drilling device may then be transported to another location for thedrilling of another hole.

In FIGURES IX-XI is shown a modified structure for detachably connectingthe rotating spindle and the adapter head against relative rotationaland longitudinal movement, whereby the inner drill pipe and the outerdrill pipe may be detachably connected for rotation together.

Referring to the drawings of such modified form, the

numeral 91 generally indicates the modified adapter head which includesa tubular body 92 having an integral upwardly extending neck 93 thereon,on which neck is formed male threads 94 for threaded attachment to therotatable tubular part 55 of the rotary swivel 28.

The tubular body 92 has male threads 935 formed on the lower end thereofwhich may be threadedly attached to the sub 96. The sub 96 is secured toa section of drill pipe '97 by means of a weld 97a. The section of pipe97, which constitutes a section of the inner drill pipe, has provided onits other end a sub (not shown) like that shown at 96, which may bethreadedly attached to another section of the inner drill pipe.

An annular shoulder 98 is secured to the tubular body 92 by means ofwelds 99 and 99a.

An annular skirt 1% is secured to the shoulder 98 by means of a weld101.

The skirt 1130 has a plurality of J-slots 102 formed therein, eachJ-slot 102 including a horizontal portion 103 communicating with avertical opening 104 which is arranged to receive the lock pins 115,hereinafter described.

The tubular spindle body 1105 includes an integral bearing retainerskirt 1%. The upper bearing 1%! and the lower bearing 1% are spacedapart and retained in place against outward movement by a bearingretainer ring 169, the upper end of which extends under the skirt 1%. Apair of cars 11% are formed on the bearing retainer ring 109, to whichthe bail 111 is pivotally attached on the bearings 11 1a.

The bearing assembly is held together by means of -a retainer nut 112threadedly engaged to the spindle body 1115. The bearing retainer nut issecured against rotation by a set screw 113, after it has been rotatedin place. A seal 118 is disposed between the bearing retainer nut 112and the retainer ring 109 to prevent the escape of lubrication from thebearing assembly.

A lock ring 1 14 is secured to the spindle body 105 by means of a weld114a.

A plurality of lock pins 115, there being one for each of the J-slots102, are secured to the lock ring 114 by means of welds 116, such lockpins being extended through passages in the wall of the lock ring 114and fixedly attached therein by the welds 116. The lock pins 115 extendoutwardly of the lock ring 114 and are so arranged about the peripherythereof that they may be placed in alignment with the vertical openings194 of the J-slots lit-2.

A seal ring 118 is provided between the shoulder 98 and the lock ring114, said seal ring being held in place by the screws 119.

To attach the modified adapter head 91 hereinbefore described, to themodified spindle body 195, the skirt or depending portion 109 ispositioned over the lock ring 114, and the vertical openings 104- of theJ-slots 1632 are brought into alignment with the lock pins 115, so thatthe lock pins 115 may be passed through the vertical passages 1M and bebrought into alignment with the horizontal portion 133 of the J-slots1&2 when the skirt 1% is positioned in overlapping relationship to thelock ring 114. The adapter head 91 is then rotated counter clockwisewith relation to the spindle body 165, thereby causing the lock pins 115to move laterally in the hori: zontal portions 1% of the J-slots 102. Itwill be seen that the inner drill pipe and outer drill pipe are thusdetachably secured together against relative longitudinal movement andthat when the spindle body 105 is rotated clockwise by means of thedrive mechanism hereinbefore described, the lock pins 115, by virtue'oftheir engagement with the end of the horizontal portions 103 of theJ-slots 102, cause the rotation of the adapter head 91 and the innerdrill pipe attached thereto. The pins 115 and the J-slots 1612 provide amodified form of slidably keyed connection between the adapter head 91and the rotating spindle 105, and thereby provides a detachableconnection between the telescoping inner and outer' drill pipes so thatthe drill pipes may be sepa-. Such bayonet type conrately withdrawn fromthe hole. nection provides means to detachably secure the inner andouter drill pipe together for preventing relative rotation therebetweenand means for preventing relative longitudinal movement thereb etweenwhile drilling.

The adapter head 91, and the rotating spindle 155, may be easilyseparated by simply rotating the skirt 1% in a clockwise direction withrelation to the lock ring 114 so as to bring the lock pins in alignmentwith the vertical openings 164, so that the adapter headand the rotatingspindle may be separated by relative longitudinal movement.

The procedure for drilling and the assembly of the inner and outer drillpipes and the placing of the explosives in the hole and detonating sameis the same asv that described with relation to the first form hereindescribed.

It will be seen that we have provideda drilling device for the purposesherein described, wherein there is provided an inner drill pipe whichmay be withdrawn from an outer drill pipe for the purpose of leaving acasing in the hole while explosive charges or otherdevices are loweredinto the hole, thereby facilitating the placing of. such explosivecharges into the hole and eliminating the possibility of the holebecoming obstructed by loose material prior to lowering the explosivecharge therein. Such a drilling device results in a great savings intime and expense in carrying out quarrying or geophysical exploration.

It will be understood that this invention would have general applicationin any drilling operation where it is desired to leave a casing in thehole after it has been drilled, thus eliminating the necessity ofrunning and setting a separate casing.

It will be apparent that other and further forms of my invention, inaddition to that disclosed herein, may be devised without departing fromthe spirit and scope of the appended claims.

I claim:

1. In a drilling device, an outer drill pipe; a rotatable spindleattached to the upper end of the outer drill pipe; an inner drill pipetelescopically disposed in the outer drill pipe; a hollow head attachedto the upper end of the inner drill pipe and being positioned in thespindle; and key and keyway means arranged between the spindle and thehead whereby they may be rotated together; and means to secure thespindle and head together against relative longitudinal movement.

2. in a drilling device, an outer drill pipe; a rotatable spindleattached to the upper end of the outer drill pipe; an inner drill pipetelescopically disposed in the outer drill pipe; a hollow head attachedto the upper end of the inner drill pipe, and being positioned in thespindle; longitudinally slidable key and keyway means arranged betweenthe spindle and the head whereby they may be rotated together; means tosecure to spindle and head together against relative longitudinalmovement; and means to rotate the outer drill pipe.

3. In a drilling device, an outer drill pipe; a rotatable spindleattached to the upper end of the outer drill pipe; an inner drill pipetelescopically disposed in the outer drill pipe; a hollow head attachedto the upper end of the inner drill pipe and being positioned in thespindle; longitudinally slidable key and keyway means arranged betweenthe spindle and the head whereby they maybe rotated together; means torotate the outer drill pipe; and means for securing the spindle and thehead against relative longitudinal movement, said means being releasableto permit the inner drill pipe to be Withdrawn from the outer drillpipe.

4. In a drilling device, an outer drill pipe; a rotatable spindleattached to the upper end of the outer drill pipe; an inner drill pipetelescopically disposed in the outer drill pipe; a hollow head attachedto the upper end of the inner drill pipe, and being positioned in thespindle; longitudinally slidable key and keyway means arranged betweenthe spindle and the head; means to secure the spindle and head togetheragainst relative longitudinal movement; and a fluid circulating headattached in communication with the hollow head.

5. In a drilling device; an outer drill pipe; a rotatable spindleattached to the upper end of the outer drill pipe; an inner drill pipetelescopically disposed in the outer drill pipe; a hollow head attachedto the upper end of the inner drill pipe, and being positioned in thespindle; the said hollow head being slidably keyed to the spindle forrotation therewith; and means to secure the spindle and head togetheragainst relative longitudinal movement.

6. In a drilling device, an outer drill pipe, a rotatable spindleattached to the upper end of the outer drill pipe; an inner drill pipetelescopically arranged within the outer drill pipe; a hollow headattached to the upper end of the inner drill pipe and being positionedin the spindle; means disengageably attaching the spindle to the head toprevent relative rotation therebetween; and means to secure the spindleand head together against relative longtudinal movement.

7. In a drilling device, an outer drill pipe; a rotatable spindleattached to the upper end of the outer drill pipe; an inner drill pipetelescopically arranged within the outer drill pipe; a hollow headattached to the upper end of the inner drill pipe and being positionedin the spindle; longitudinally slidably related means on the head and inthe spindle to prevent relative rotation therebetween; and disengageablyattached means between the head and the spindle to prevent longitudinalmovement therebetween.

8. The combination called for in claim 7 wherein the longitudinally,slidably related means consists of key slots on the inner side of thespindle and complementary keys formed on the outer surface of the head.

9. The combination called for in claim 7 wherein the disengageablyattached means comprises a nut threadedly engaged about the spindle andhaving a part engaged with the supper side of the head.

10. In a drilling device, an outer drill pipe, a rotatable spindleattached to the upper end of the outer drill pipe; an inner drill pipetelscopically arranged within the outer drill pipe; a hollow headattached to the upper end of the inner drill pipe and being positionedin the spindle; and means disengageably attaching the spindle to thehead to prevent relative rotation and longitudinal movementtherebetween.

11. In a drilling device; an outer drill pipe; a rotatable spindleattached to the upper end of the outer drill pipe;

an inner drill pipe telescopically arranged within the outer drill pipe;a hollow head attached to the upper end of the inner drill pipe andbeing positioned in the spindle; and means disengageably attaching thespindle to the head, said means including a portion depending from thehead overlapping the upper end of the spindle; and means disengageablyattaching the overlapping portion to the spindle.

12. The combination called for in claim 11 wherein the meansdisengageably attaching the overlapping portion to the spindle consistsof a bayonet joint connection between such members.

13. The combination called for in claim 11 wherein the meansdisengageably attaching the overlapping portion to the spindle comprisesat least one J-slot in the overlapping portion, and a pin extendingoutwardly of the spindle arranged to engage the J-slot.

14. In a drilling device, an outer drill pipe; a rotatable spindleattached to the upper end of the outer drill pipe; an inner drill pipetelescopically arranged within the outer drill pipe; a hollow headattached to the upper end of the inner drill pipe and being positionedin the spindle; an annular skirt depending from the head arranged tooverlap the upper end of the spindle; a plurality of J-slots arranged inthe wall of the skirt; and a plurality of lock pins arranged about thespindle in position to engage in the J-slots to thereby disengageablyattach the head to the spindle.

15. The combination called for in claim 10 wherein the meansdisengageably attaching the spindle to the head consists of a bayonetjoint connection between such members.

16. In a drilling device, an outer drill pipe; a rotatable spindleattached to the upper end of the outer drill pipe; an inner drill pipetelescopically arranged Within the outer drill pipe; a hollow headattached to the upper end of the inner drill pipe and being positionedin the spindle; an annular skirt depending from the head arranged tooverlap the upper end of the spindle; and means defining a bayonet jointconnection between said skirt and said spindle to thereby disengageablyattach the head to the spindle.

References (Iited in the file of this patent UNITED STATES PATENTS1,908,227 Dodds May 9, 1933 2,684,229 Bergstrom July 20, 1954 2,784,949Peck Mar. 12, 1957 FOREIGN PATENTS 1,042,438 France June 3, 1953

